System and method of providing hydraulic pressure for mechanical work from an engine lubricating system

Abstract

The method provides hydraulic pressure for mechanical work from an engine lubricating system in an internal combustion engine by supplying oil to an engine lubrication gallery for lubricating the engine and to at least one variable oil demand accessory. Each of the variable oil demand accessories has an individual pressure regulator. The output of the variable displacement pump is regulated based on the sum of fluid flow required by the engine lubricating system and the engine accessories, regardless of the engine output. The demand for fluid is determined by the individual pressure regulators on each of the engine accessories. In a preferred embodiment, an accumulator stores high-pressure fluid to be used to power the hydraulic accessories.

1. A method of providing hydraulic pressure for mechanical work from an engine lubricating system in an internal combustion engine, comprising the steps of:
 a) supplying oil from a variable displacement pump to an engine lubrication gallery for lubricating the engine; 
 b) supplying oil from the variable displacement pump to at least one engine accessory having a variable oil demand, each accessory having a pressure regulator; 
 c) regulating an output of the variable displacement pump to a sum of a fluid flow required by the engine lubrication system and a fluid demand generated by the pressure regulators; and 
 d) supplying oil from the variable displacement pump to an accumulator for storing an accumulator hydraulic pressure for later use as mechanical work. 
 
   
   
     2. The method of  claim 1 , wherein the at least one engine accessory is selected from the group consisting of:
 a) a hydraulic motor driven cooling fan; 
 b) a power steering system; 
 c) a hydraulic motor driven air conditioning compressor; 
 d) a hydraulic motor driven engine coolant pump; 
 e) a hydraulic motor driven alternator; 
 f) a hydraulic motor driven supercharger; 
 g) an electrohydraulic valve actuation system; and 
 h) a suspension actuator motor. 
 
   
   
     3. The method of  claim 1 , wherein the fluid flow for lubricating the engine is based on engine parameters. 
   
   
     4. The method of  claim 1 , further comprising the step of using the accumulator hydraulic pressure to power the at least one hydraulic accessory. 
   
   
     5. The method of  claim 1 , further comprising the step of using the accumulator hydraulic pressure via the variable displacement pump to add work to a crankshaft driven by the engine. 
   
   
     6. The method of  claim 1 , further comprising the step of supplying oil from a fixed displacement pump to the engine lubrication gallery for lubricating the engine, wherein the variable displacement pump supplies only enough oil to make up a difference between what the engine requires and what the fixed displacement pump supplies. 
   
   
     7. A hydraulic on-demand engine accessory drive system for an internal combustion engine comprising:
 a variable displacement pump having a pump fluid communication input from a sump and a pump fluid communication output to a high-pressure manifold; 
 a variable displacement pump controller mounted to the variable displacement pump and in communication with an ECU; 
 an engine having an engine fluid communication input from the high-pressure manifold and an engine fluid communication output to the sump; 
 at least one engine accessory having a variable oil demand and a pressure regulator, wherein the pressure regulator is in fluid communication with and has a regulator input from the high-pressure manifold and a regulator output to the sump; and 
 an accumulator having a fluid communication line to the high-pressure manifold for storing and supplying energy as an accumulator fluid pressure; 
 wherein the pump fluid communication output is regulated by the variable displacement pump controller based on a sum of flow required by the pressure regulator of the at least one engine accessory and the engine for lubrication, regardless of engine output. 
 
   
   
     8. The system of  claim 7 , wherein the high-pressure manifold powers the pressure regulator. 
   
   
     9. The system of  claim 7 , wherein the ECU monitors sensors on the engine. 
   
   
     10. The system of  claim 9 , wherein the sensors monitor temperature and speed of the engine. 
   
   
     11. The system of  claim 7 , wherein the at least one engine accessory is selected from the group consisting of:
 a) a hydraulic motor driven cooling fan; 
 b) a power steering system; 
 c) a hydraulic motor driven air conditioning compressor; 
 d) a hydraulic motor driven engine coolant pump; 
 e) a hydraulic motor driven alternator; 
 f) a hydraulic motor driven supercharger 
 g) an electrohydraulic valve actuation system; and 
 h) a suspension actuator motor. 
 
   
   
     12. The system of  claim 7 , further comprising an oil cooler in the regulator output of the at least one engine accessory to the sump. 
   
   
     13. The system of  claim 7 , wherein the ECU controls whether the accumulator receives oil, maintains oil, or supplies oil. 
   
   
     14. The system of  claim 7 , wherein the accumulator hydraulic pressure powers the at least one hydraulic accessory. 
   
   
     15. The system of  claim 7 , wherein the accumulator hydraulic pressure adds work via the variable displacement pump to a crankshaft driven by the engine. 
   
   
     16. The system of  claim 15 , wherein the variable displacement pump replaces a conventional electric starter motor used for starting the engine. 
   
   
     17. The system of  claim 7 , further comprising a fixed displacement pump having a fixed pump fluid communication input from the sump and a fixed pump fluid communication output to the engine lubrication gallery for lubricating the engine. 
   
   
     18. The system of  claim 17 , wherein the variable displacement pump supplies only enough oil to make up a difference between what the engine requires and what the fixed displacement pump supplies. 
   
   
     19. A hydraulic on-demand engine accessory drive system for an internal combustion engine comprising:
 a variable displacement pump having a pump fluid communication input from a sump and a pump fluid communication output to a high-pressure manifold; 
 a variable displacement pump controller mounted to the variable displacement pump and in communication with an ECU; 
 an engine having an engine fluid communication input from the high-pressure manifold and an engine fluid communication output to the sump; and 
 at least one engine accessory having a variable oil demand and a pressure regulator, wherein the pressure regulator is in fluid communication with and has a regulator input from the high-pressure manifold and a regulator output to the sump; and 
 wherein the pump fluid communication output is regulated by the variable displacement pump controller based on a sum of flow required by the pressure regulator of the at least one engine accessory and the engine for lubrication, regardless of engine output. 
 
   
   
     20. The system of  claim 19 , wherein the high-pressure manifold powers the pressure regulator. 
   
   
     21. The system of  claim 19 , wherein the ECU monitors sensors on the engine. 
   
   
     22. The system of  claim 21 , wherein the sensors monitor temperature and speed of the engine. 
   
   
     23. The system of  claim 19 , wherein the at least one engine accessory is selected from the group consisting of:
 a) a hydraulic motor driven cooling fan; 
 b) a power steering system; 
 c) a hydraulic motor driven air conditioning compressor; 
 d) a hydraulic motor driven engine coolant pump; 
 e) a hydraulic motor driven alternator; 
 f) a hydraulic motor driven supercharger 
 g) an electrohydraulic valve actuation system; and 
 h) a suspension actuator motor. 
 
   
   
     24. The system of  claim 19 , further comprising an oil cooler in the regulator output of the at least one engine accessory to the sump. 
   
   
     25. The system of  claim 19 , further comprising a fixed displacement pump having a fixed pump fluid communication input from the sump and a fixed pump fluid communication output to the engine lubrication gallery for lubricating the engine. 
   
   
     26. The system of  claim 25 , wherein the variable displacement pump supplies only enough oil to make up a difference between what the engine requires and what the fixed displacement pump supplies.